1 /******************************************************************************
2 *******************************************************************************
3 **
4 **  Copyright (C) Sistina Software, Inc.  1997-2003  All rights reserved.
5 **  Copyright (C) 2004-2011 Red Hat, Inc.  All rights reserved.
6 **
7 **  This copyrighted material is made available to anyone wishing to use,
8 **  modify, copy, or redistribute it subject to the terms and conditions
9 **  of the GNU General Public License v.2.
10 **
11 *******************************************************************************
12 ******************************************************************************/
13 
14 #ifndef __DLM_DOT_H__
15 #define __DLM_DOT_H__
16 
17 /*
18  * Interface to Distributed Lock Manager (DLM)
19  * routines and structures to use DLM lockspaces
20  */
21 
22 /* Lock levels and flags are here */
23 #include <linux/dlmconstants.h>
24 #include <linux/types.h>
25 
26 typedef void dlm_lockspace_t;
27 
28 /*
29  * Lock status block
30  *
31  * Use this structure to specify the contents of the lock value block.  For a
32  * conversion request, this structure is used to specify the lock ID of the
33  * lock.  DLM writes the status of the lock request and the lock ID assigned
34  * to the request in the lock status block.
35  *
36  * sb_lkid: the returned lock ID.  It is set on new (non-conversion) requests.
37  * It is available when dlm_lock returns.
38  *
39  * sb_lvbptr: saves or returns the contents of the lock's LVB according to rules
40  * shown for the DLM_LKF_VALBLK flag.
41  *
42  * sb_flags: DLM_SBF_DEMOTED is returned if in the process of promoting a lock,
43  * it was first demoted to NL to avoid conversion deadlock.
44  * DLM_SBF_VALNOTVALID is returned if the resource's LVB is marked invalid.
45  *
46  * sb_status: the returned status of the lock request set prior to AST
47  * execution.  Possible return values:
48  *
49  * 0 if lock request was successful
50  * -EAGAIN if request would block and is flagged DLM_LKF_NOQUEUE
51  * -DLM_EUNLOCK if unlock request was successful
52  * -DLM_ECANCEL if a cancel completed successfully
53  * -EDEADLK if a deadlock was detected
54  * -ETIMEDOUT if the lock request was canceled due to a timeout
55  */
56 
57 #define DLM_SBF_DEMOTED		0x01
58 #define DLM_SBF_VALNOTVALID	0x02
59 #define DLM_SBF_ALTMODE		0x04
60 
61 struct dlm_lksb {
62 	int 	 sb_status;
63 	__u32	 sb_lkid;
64 	char 	 sb_flags;
65 	char *	 sb_lvbptr;
66 };
67 
68 /* dlm_new_lockspace() flags */
69 
70 #define DLM_LSFL_NODIR		0x00000001
71 #define DLM_LSFL_TIMEWARN	0x00000002
72 #define DLM_LSFL_FS     	0x00000004
73 #define DLM_LSFL_NEWEXCL     	0x00000008
74 
75 #ifdef __KERNEL__
76 
77 struct dlm_slot {
78 	int nodeid; /* 1 to MAX_INT */
79 	int slot;   /* 1 to MAX_INT */
80 };
81 
82 /*
83  * recover_prep: called before the dlm begins lock recovery.
84  *   Notfies lockspace user that locks from failed members will be granted.
85  * recover_slot: called after recover_prep and before recover_done.
86  *   Identifies a failed lockspace member.
87  * recover_done: called after the dlm completes lock recovery.
88  *   Identifies lockspace members and lockspace generation number.
89  */
90 
91 struct dlm_lockspace_ops {
92 	void (*recover_prep) (void *ops_arg);
93 	void (*recover_slot) (void *ops_arg, struct dlm_slot *slot);
94 	void (*recover_done) (void *ops_arg, struct dlm_slot *slots,
95 			      int num_slots, int our_slot, uint32_t generation);
96 };
97 
98 /*
99  * dlm_new_lockspace
100  *
101  * Create/join a lockspace.
102  *
103  * name: lockspace name, null terminated, up to DLM_LOCKSPACE_LEN (not
104  *   including terminating null).
105  *
106  * cluster: cluster name, null terminated, up to DLM_LOCKSPACE_LEN (not
107  *   including terminating null).  Optional.  When cluster is null, it
108  *   is not used.  When set, dlm_new_lockspace() returns -EBADR if cluster
109  *   is not equal to the dlm cluster name.
110  *
111  * flags:
112  * DLM_LSFL_NODIR
113  *   The dlm should not use a resource directory, but statically assign
114  *   resource mastery to nodes based on the name hash that is otherwise
115  *   used to select the directory node.  Must be the same on all nodes.
116  * DLM_LSFL_TIMEWARN
117  *   The dlm should emit netlink messages if locks have been waiting
118  *   for a configurable amount of time.  (Unused.)
119  * DLM_LSFL_FS
120  *   The lockspace user is in the kernel (i.e. filesystem).  Enables
121  *   direct bast/cast callbacks.
122  * DLM_LSFL_NEWEXCL
123  *   dlm_new_lockspace() should return -EEXIST if the lockspace exists.
124  *
125  * lvblen: length of lvb in bytes.  Must be multiple of 8.
126  *   dlm_new_lockspace() returns an error if this does not match
127  *   what other nodes are using.
128  *
129  * ops: callbacks that indicate lockspace recovery points so the
130  *   caller can coordinate its recovery and know lockspace members.
131  *   This is only used by the initial dlm_new_lockspace() call.
132  *   Optional.
133  *
134  * ops_arg: arg for ops callbacks.
135  *
136  * ops_result: tells caller if the ops callbacks (if provided) will
137  *   be used or not.  0: will be used, -EXXX will not be used.
138  *   -EOPNOTSUPP: the dlm does not have recovery_callbacks enabled.
139  *
140  * lockspace: handle for dlm functions
141  */
142 
143 int dlm_new_lockspace(const char *name, const char *cluster,
144 		      uint32_t flags, int lvblen,
145 		      const struct dlm_lockspace_ops *ops, void *ops_arg,
146 		      int *ops_result, dlm_lockspace_t **lockspace);
147 
148 /*
149  * dlm_release_lockspace
150  *
151  * Stop a lockspace.
152  */
153 
154 int dlm_release_lockspace(dlm_lockspace_t *lockspace, int force);
155 
156 /*
157  * dlm_lock
158  *
159  * Make an asyncronous request to acquire or convert a lock on a named
160  * resource.
161  *
162  * lockspace: context for the request
163  * mode: the requested mode of the lock (DLM_LOCK_)
164  * lksb: lock status block for input and async return values
165  * flags: input flags (DLM_LKF_)
166  * name: name of the resource to lock, can be binary
167  * namelen: the length in bytes of the resource name (MAX_RESNAME_LEN)
168  * parent: the lock ID of a parent lock or 0 if none
169  * lockast: function DLM executes when it completes processing the request
170  * astarg: argument passed to lockast and bast functions
171  * bast: function DLM executes when this lock later blocks another request
172  *
173  * Returns:
174  * 0 if request is successfully queued for processing
175  * -EINVAL if any input parameters are invalid
176  * -EAGAIN if request would block and is flagged DLM_LKF_NOQUEUE
177  * -ENOMEM if there is no memory to process request
178  * -ENOTCONN if there is a communication error
179  *
180  * If the call to dlm_lock returns an error then the operation has failed and
181  * the AST routine will not be called.  If dlm_lock returns 0 it is still
182  * possible that the lock operation will fail. The AST routine will be called
183  * when the locking is complete and the status is returned in the lksb.
184  *
185  * If the AST routines or parameter are passed to a conversion operation then
186  * they will overwrite those values that were passed to a previous dlm_lock
187  * call.
188  *
189  * AST routines should not block (at least not for long), but may make
190  * any locking calls they please.
191  */
192 
193 int dlm_lock(dlm_lockspace_t *lockspace,
194 	     int mode,
195 	     struct dlm_lksb *lksb,
196 	     uint32_t flags,
197 	     void *name,
198 	     unsigned int namelen,
199 	     uint32_t parent_lkid,
200 	     void (*lockast) (void *astarg),
201 	     void *astarg,
202 	     void (*bast) (void *astarg, int mode));
203 
204 /*
205  * dlm_unlock
206  *
207  * Asynchronously release a lock on a resource.  The AST routine is called
208  * when the resource is successfully unlocked.
209  *
210  * lockspace: context for the request
211  * lkid: the lock ID as returned in the lksb
212  * flags: input flags (DLM_LKF_)
213  * lksb: if NULL the lksb parameter passed to last lock request is used
214  * astarg: the arg used with the completion ast for the unlock
215  *
216  * Returns:
217  * 0 if request is successfully queued for processing
218  * -EINVAL if any input parameters are invalid
219  * -ENOTEMPTY if the lock still has sublocks
220  * -EBUSY if the lock is waiting for a remote lock operation
221  * -ENOTCONN if there is a communication error
222  */
223 
224 int dlm_unlock(dlm_lockspace_t *lockspace,
225 	       uint32_t lkid,
226 	       uint32_t flags,
227 	       struct dlm_lksb *lksb,
228 	       void *astarg);
229 
230 #endif				/* __KERNEL__ */
231 
232 #endif				/* __DLM_DOT_H__ */
233 
234